TDE1890 - TDE1891
- All electrical parameters of the device, con-
cerning the calculation, are at maximum val-
ues.
- Thermal shutdown threshold is at minimum
value.
Therefore:
Vs = 30V, RDSON0 = 0.23Ω, Iq = 8mA, Ios = 4mA
@ Vos = 2.5V, ΘLim = 135°C
Rthj-amb = 35°C/W
It follows:
Ioutx = 2.5A, RDSONx = 0.386Ω, Pq = 240mW,
Pos = 110mW
From equation 4 we can see that, without any
heatsink, it is not possible to operate in the ON
steady state at the maximum current value. A
derating curve for this case is reported in fig. 7.
Using an external heatsink, in order to obtain a to-
tal Rth of 15°C/W, we obtain the derating curve
reported in fig. 8.
Figure 6: Application Circuit
DC BUS 24V +/-25%
+IN
+
-IN
-
CONTROL
LOGIC
+Vs
OUTPUT
D1
µP POLLING
D2
GND
Ios
OUTPUT STATUS
LOAD
D93IN014
Figure 7: Max. Output Current vs. Ambient
Temperature (Multiwatt without
heatsink, Rth j-amb = 35°C/W)
D93IN033
Io
(A)
2.5
2.0
1.5
1.0
0.5
0.0
0
20 40 60 80 100 120 Tamb (°C)
8/12
Figure 8: Max. Output Current vs. Ambient
Temperature (Multiwatt with heatsink,
Rth j-amb = 15°C/W)
D93IN020A
Io
(A)
2.5
2.0
1.5
1.0
0.5
0.0
0
20 40 60 80 100 120 Tamb (°C)